Electromotor-driven textile mill spindles



K. BEERLI Filed Feb. 5, 1962A ELECTROMOTOR-DRIVEN TEXTILE MILL SPINDLES United States Patent Oii ice 3,095,6874 Patented July 2, 1963 Spindel, Motorenund Maschinenfabrik A.G., Uster, Switzerland Filed Feb. 5, 1962, Ser. No. 170,982 Claims priority, application Switzerland Feb. 17, 1961 Y 4 Claims. (Cl. 57-100) The present invention relates to a textile mill spindle drivenvby an electromotor the rotor of which is fixed to the spindle shaft, said spindle comprising a bearing sleeve which connects a ioot bearing to 'a collar bearing in which the spindle shaft is rotatably supported and which 1s supported in a housing adapted to be mounted on the frame of a texltile machine. r

Textile mill spindles of this kind have been proposed in which the bearing lsleeve is rigidly xed to the housing while the housing is yieldingly supported in the frame of the textile machine in such manner that it can effect damped movements in tnansverse directions with reference to the spindle axis. In these known spindles, the moments occurring at high speedsof rotation and which rend to induce angular movements of the spindle shaft with reference to the spindle axis are kept small by locating the centreof gravity of the rotating masses, which comprise mainly the rotor of the electromotor and the yarn package seated on the spindle shaft, approximately in the plane of Ithe collar bearing. This can be attained with certain kinds of spindles only. Moreover, such spindles do not tend to assume a predetermined fixed axis of rotation while they are running. Therefore, they could not be used asspindles for ring spinning machines since no coaxiality of each spindle and its ring could be obtained.

To obviate this drawback, it also has beensuggested for such textile mill spindles to have the housing mounted immovably in the spindle frame and to have the bearing sleeve supported in the housing by a ball and socket articulation, as a socalled brake ring sleeve According to a further known arrangement, the spindle shaft is made hollow and it 'is supported on a nonrotating spindle axle -Which in turn 4is swingably mounted in 'the housing Iby means of a balland socket articulation and provided with means for damping its swinging movements.

l The two last-mentioned arrangements have not been successful either since in electromotor-driven spindles in which the rotating mass of the rotor of the electroinotor adds itself to -that of the yarn package, the mounting comprising `a ball and socket articulation and damping means such `as a brake ring or the like, known with spindles ldriven from outside, is unable to cope with the increased iorces occurring at high speeds of rotation. ,These forces are particularly high if due to the limitations imposed on the spindle diameter by the construction of the textile machine, both -the yarnpackage and the electromotor have to be `disposed above the ball and socket articulation. A sturdier construction of the hall and socket articulation and the provision of more eiective damping means are prevented -as well by this diameter limitation.

Further, textile mill spindles without electromotor are known which comprises a bearing sleeve containing a foot bearing and la collar bearing for the spindle shaft, the foot bearing portion of the sleeve being yieldingly connected to the collar bearing portion and the collar bearing being constructed to lallow for small transverse swinging movements of the spindle shaft. Such an arrangement would not be advantageous for a spindle comprising an electromotor the rotor of which is xed to the spindle shaft, since the stator, whether it be connected to the foot bearing portion of the bearing sleeve, to its collar bearing portion, or tothe housing, could not follow the transverse swinging movements of the spindle shaft and of the rotor in such la manner as to leave the air gap between the rotor and the stator unaltered.

In contrast to these Iarrangements, in the textile mill spindle and electromotor assembly according to the invention, at least part of the bearing sleeve iorms a rigid connection between the foot bearing `and the collar'bearing and is itself rigidly connected to the stator of the electromotor while being yielding and swingably connected to at least that portion off the housing which is to be connected to the fname of lthe textile machine for supporting the spindle.

Thereby, it is obtained that the stator of the electromotor takes part in the transverse swinging movements of the bearing sleeve, of the spindle shaft rotatably supported therein, and of the rotor supported by the latter, so that the air Igap between the rotor fixed on the spindle shaft and the stator connected to the bearing sleeve does not vary to sany practically relevant extent. This in turn results in the possibility of minimizing the width of that air gap, of improving the eiciency of the motor, and of diminishing its dimensions and weight.

In FIG. 1 of the accompanying drawing, an embodiment of -the textile mill spindle and electromotor is represented by vway of example, in axial section, and

FIG. 2 of the said drawing represents, also by Way of example, a modification thereof, in axial section as well.

In FIG. 1, 1 is a tubular housing which is closed at its lower end and provided externally with a screw thread whereby it is secured at the desired ievel in a fly frame 3 by means of `a pair of nuts 2. The pontion of the housing 1 lwhich is above the screw thread serves to connect the 'lower portion thereof, which is rigidly' secured to the fly frame, to a rigid, tubular bearing sleeve 4 secured to the housing.

At its lower end, the bearing sleeve 4 provides a foot bearing l6 for the spindle shaft 5 and at its upper end, lit has an extelnal flange 7 seated on an internal shoulder 8 of the housing -1. On the upper side of the ange 7, a spacing ring 9 supports the outer race ring 10` of a radial roller bearing 11 which serves as the coilar bearing for the spindle shaft 5. Finally, a cover ring 12 having an upwardly tapered peripheral surface is rested on the outer race ring 10. The peripheral wall 13y of the housing 1 which surrounds the flange 7 of the bearing sleeve parts 7, 9, 10 and 12 immovably assembled under high axial pressure without exerting through the outer, race L any undesirable radial pressure on the rollers of the bearing 11 (see my U.S. Patent No. 2,777,739).

Below the internal shoulder 8 of the housing 1, i.e. outside its contact surface with the bearing sleeve 4, a number of transverse slots 14 are milled into the said connecting portion of the housing 1, two such slots being provided in each of four parallel planes and the pair of slots in each plane being offset 9() degrees to the pair of slots in the next plane. Due to these transverse slots, the said connecting portion of the housing 11 forms a plurality of flexible ring segments extending peripherally in different planes, each ring segment being connected at one point to a ring segment in the one adjacent plane and at a point angul-arly offset therefrom either to a ring segment in the opposite adjacent plane, or to the adjacent solid portion of the housing. Thus, the connecting portion of the housing 1 is yieldable and it permits the bearing sleeve 4 to effect lateral swinging movements even though this bearing sleeve is rigidly connected to the housing 1 at the seating surface 8.

Up to a certain level, the lower part iof the housing 1 is filled with oil which serves on one hand for lubricating the foot bearing 6 and on the other hand for damping the transverse swinging movements of the bearing sleeve 4. Between the latter and the vwall of the housing 1 a number of cup-shaped elements 15 having apertures in their walls for the passage of the oil are inserted with some play in order to increase the damping of the swinging movements of the bearing sleeve beyond proportionality of its deviation from its axial position.

Above the transverse slots 14, a sleeve 16 is forced onto the peripheral wall 13 of the connecting portion of the housing 1, which is slightly conical externally. In its lower part, the bore of that sleeve 16 is of somewhat greater diameter than the external diameter of the housing 1 at the respective level, so that the sleeve 16 can take part in the transverse swinging movements of the bearing sleeve 4 without abutting the housing 1. The said sleeve 16 carries externally the laminated stator core 18 with external windings 17 of an electromotor Iwhich also comprises an outer rotor 19. The laminated stator core 1S is supported by a lower end ring 20 which in turn is seated on an external flange 21 of the sleeve 16. At its upper end, the stator core is retained by a similar end ring 20, a spacing ring 22 vand a circlip 23 lodged in an annular groove of the sleeve 16.

The rotor 19` of the motor comprises ya laminated core 25 into notches `of which a squirrel-cage armature 24 made from non-ferromagnetic metal is sunk. The rotor is screwed to an intermediate member 26 which itself is fixed to a yarn supporting member 27 itself forced onto the spindle shaft 5 of which it forms an extension. Thus, the external rotor 19` is rigidly connected to the spindle shaft 5. As will be seen from the drawing, the center of gravity of the stator and rotor, which will be on a plane extending transversely through the midpoint of the stator and rotor assembly, will substantially coincide with the yieldable connecting portion of the housing. The yarn supporting member 27, which for space reasons is not fully shown in FIG. 1, is constructed in known manner for receiving a yarn package or bobbin.

In the modification shown -in FIG. 2, the bearing sleeve 4 has an enlarged head 31 having a peripheral Wall 32 and an inner shoulder 33 which, in the same manner as the peripheral wall 13 and the inner shoulder 8 of the housing `1 in the embodiment according to FIG. l, provide a lodging for the collar bearing 11. In the present modification, the housing 1 ends below the head 31 of the bearing sleeve and has no transverse slots. However, a tubular connecting portion 34 of the bearing sleeve 4 extends downwards into the housing 1. The lowermost part of that connecting portion is forced into the bore of the housing `1, but higher up that bore is somewhat enlarged and leaves the connecting portion 34 free.

Above its lower-most part forced into the housing bore, in the zone in which Vthat bore is enlarged, the connecting portion 34 has transverse slots 35 milled into it, these slots being in different planes and angularly offset with reference to each other. They render the tubular connecting portion 34 yieldable and they permit that portion of the bearing sleeve 4 in which the spindle shaft 5 is rotatably supported by means of the bearings 6 `and 11, to effect swinging movements to all sides.

The sleeve 16 which carries the stator 18 of the electromotor 18, =19 in this case is forced onto the peripheral wall 32 of the head 31 of the bearing sleeve 4 so that this sleeve 16 and the stator 18 take part in the swinging movements of the bearing sleeve. Thus, the stator 18 effects practically the same transverse swinging movements as the rotor `19 which is connected to the spindle shaft 5 so that the air gap between the stator 18 and the rotor 19 remains constant and can be made very narrow.

The bearing sleeve could also be made from several parts rigidly connected to each other by anging, shrinking, and the like, one of these parts containing the collar bearing, another containing the foot bearing, and a third one yieldingly connecting the said two others to the housing in such manner as to permit them to swing laterally with reference to it.

The whole bearing sleeve might also be swingably connected to the casing by a separate resilient element. Like the corresponding portion of the housing in FIG. 1 and of the bearing sleeve in FIG. 2, this resilient element could comprise a plurality of ring segments disposed in several parallel transverse planes, angularly offset with reference to each other and mutually connected, integrally or otherwise, by bridges, these segments being separated from each `other between the bridges by transverse slots. These ring segments could be made jointly from one piece into which the transverse slots are milled, or they could be made severally each as one piece. The yielding element connecting the bearing sleeve Iwith the housing could also be an annulus made from steel sheet and having a U-shaped cross-section, an annular -diaphragm with or without perforations, a helical spring, a radially compressed rubber sleeve, or the like.

According to another embodiment of the invention, not shown in the drawing, the stator of the electromotor could be arranged outside the rotor. In that case the laminated stator core and the stator windings could be supported by a peripheral wall connected to the portion of the housing or bearing sleeve situated above the-ir yielding connecting portion, by means of a depending member and of a bottom extending outwardly therefrom below the rotor.

I claim:

1. An electromotor-driven textile mill spindle comprising:

(a) a substantially rigid tubular bearing sleeve,

(b) ia foot bearing, and

(c) a collar bearing both rigidly connected to said bearing sleeve,

(d) a spindle shaft rotatably supported in said foot bearing and in said collar bearing,

(e) electromotor means comprising a stator rigidly connected to said bearing sleeve and a rotor rigidly connected to said spindle shaft,

(f) a housing, and

(g) yielding connecting means swingably connecting said bearing sleeve to said housing and the center of gravity of said stator and rotor substantially coinciding with the position of said yielding connecting means.

2. Electromotor-driven textile mill spindle yas claimed in claim 1 in which said yielding connecting means is a resilient integral portion of said housing which is rigidly connected to said bearing sleeve.

3. Electromotor-driven textile mill spindle as vclaimed in claim 1 in which said yielding connecting means is a References Cited in the le of this patent resi-lient integral portion of said bearing sleeve which is rigidly connected to said housing. UNITED STATES PATENTS 4. Electromotor-driven textile mill spindle as claimed 2,474,210 Abbott 4 June 28, 1949 in claim 1 in which said yielding connecting means com- 5 2,912,815 Feather Nov, 17, 1959 prises la plurality of flexible :ring segments extending pe- 2,957,302 Lenk @131 Oct, 25, 196() ripherally in different transverse p1ames,'each ming segment being connected at Ione point to a ring segment in FOREIGN PATENTS one adjacent plane and at a point iangultarly `offset there- 84,852 NetheflaldS May 16, 1957 from to a ring segment in the opposite adjacent plane. 10 960,618 France Oct. 31, 1949 

1. AN ELECTROMOTOR-DRIVEN TEXTILE MILL SPINDLE COMPRISING: (A) A SUBSTANTIALLY RIGID TUBULAR BEARING SLEEVE, (B) A FOOT BEARING, AND (C) A COLLAR BEARING BOTH RIGIDLY CONNECTED TO SAID BEARING SLEEVE, (D) A SPINDLE SHAFT ROTATABLY SUPPORTED IN SAID FOOT BEARING AND IN SAID COLLAR BEARING, (E) ELECTORMOTOR MEANS COMPRISING A STATOR RIGIDLY CONNECTED TO SAID BEARING SLEEVE AND A ROTOR RIGIDLY CONNECTED TO SAID SPINDLE SHAFT, (F) A HOUSING, AND (G) YIELDING CONNECTING MEANS SWINGABLY CONNECTING SAID BEARING SLEEVE TO SAID HOUSING AND THE CENTER OF GRAVITY OF SAID STATOR AND ROTOR SUBSTANTIALLY COINCIDING WITH THE POSITION OF SAID YIELDING CONNECTING MEANS. 